Method of utilizing calcium-carbid refuse and product thereof.



UNITED STATES Patented May 5, 1903.

GEORGE E. COX, OF NIAGARA FALLS, NEW YORK, ASSIGNOR TO 'UN'ION CARBIDE COMPANY, OF'NIAGARA FALLS, NEW YORK, A CORPORA- TION OF VIRGINIA.

METHOD OF UTILIZING CALClUM-CARBlD REFUSE AND PRODUCT THEREOF.

SPECIFICATION forming part of Letters Patent No. 727,095, dated May 5, 1903. Application filed September 3, 1902. Serial No. 121,983. (No model.)

New York, have invented a certain new and useful Method .of Utilizing Calcium-Carbid Refuse and Product Thereof, of which the following is a specification.

The invention relates to the manufacture of commercial carbid of calcium from carbid refuse. This refuse is largely carbid-dust produced by crushing the large blocks which are taken from the furnace and which must be screened out of the commercial carbid. There is also other refuse which is partlyformed carbid mixed with unreduced materials. If this refuse be fed into the ordinary acetylene-gas generator, as it falls upon the surface of the water it spreads out and accumulates as a floating layer until the weight of the dust causes the layer to sink quickly, with immediate production of a large volume of gas which exerts undue pressure upon the generator and is liable to injure it. Many unsuccessful efforts have been made to fuse this refuse into blocks by the use of electricity;

but the conditions which must be observed to enable it to be converted into an ingot in an electric furnace have not heretofore been discovered or recognized. If the carbid refuse is supplied to the ordinary carbid-furnace in place of the usual charge of coke and lime, it is found that the furnace will not work. This is largely due to the fact that the electrical conductivity of the refuse is very high, so that the electrodes become short-circuited and destroyed, while the copper conductors to the furnace are destructively heated, the heat not being generated properly in the furnace, but in the conductors and electrodes leading to the furnace. Attempts have therefore been made to fuse this refuse material by mixing it with foreign substances which would lower its conductivity, but with unsatisfactory results, the product being a low grade of carbid that is quite uncommercial. The refuse has also been mixed with a binding material and formed into blocks which were baked in a retort, a procedure involving considerable expense and giving an inferior product.

This invention relates to the formation of commercially-pure carbid from the refuse by treating it in a suitable electric furnace. A furnace is employed -in which the electrodes are separated much farther than those of the furnace used for smelting coke and lime. Electrodes of graphite are used in preference to ordinary carbon electrodes. The conductivity of the electrodes and charge of refuse is so great that it is necessary to use a source of electric current giving a much lower voltage than that supplied to the ordinary carbid-furnac'e. For example, a furnacefor'refuse using the same electrical energyas a furnace fed with lime and coke may be operated at one-half the usual voltage and with double the usual amperage, though this ratio is variable and dependent on various conditions. Notwithstanding this decreased voltage, however, the current which is passed through the furnace is much larger than that employed in the usual carbid-furnace. It will thus be seen that the furnace for converting refuse into carbid is quite unsuited to a charge of coke and lime, while, as above stated, the ordinary furnace does not work if fed with refuse. Under the conditions specified the furnace works quietly and the refuse fed into it forms into an immense solid ingot of carbid that is commercially pure. This ingot is then broken up and packed in the ordinary way. The heat generated by the passage of the electric current through the furnace and which serves to raise the charge to a temperature at which it will melt into an ingot may be due either to the resistance of the refuse or to arcs sprung between the ends of the electrodes and the refuse or to both.

It will be seen that this new method is a distinct advance in the art of producing calcium carbid, enabling a waste product of intrinsic value to be converted into a commercial form, the ingot taken from the refusefurnace being substantially as pure as that from a furnace fed with coke and lime.

I claim- 1. The method of utilizing calcium-carbid refuse, the comminuted and relatively highly conductive waste product of carbid manufacture, which consists in interposing a body of said refuse between electrodes of higher conductivity than the refuse, and passing between the electrodes an electric current of sufficient amperage to convert the body into an ingot, as set forth.

2. The method of utilizing calcium-carbid refuse, the comminuted and relatively highly conductive waste product of carbid manufacture, which consists in interposing a body of said refuse between electrodes of higher conductivity than the refuse and spaced farther apart than those of a furnace fed with coke and lime, and passing between the electrodes an electric current of greater amperage and an ingot, as set forth.

In testimony whereof I have hereunto signed my name in the presence of two witnesses.

GEO. E. COX. Witnesses:

E. F. PRICE, GEO. H. DANFORTH. 

